The influence of mineral nutrient intakes on the severity of alveolar bone loss will be assessed in a strain of mice (STR/N) that is spontaneously susceptible to periodontal disease. In the first part of the study, the influence of zinc on bone loss will be measured, and the basis of an effect investigated via studies of bone collagen turnover and enzymes implicated in bone resorption. In the second part of the study the effect of dietary Ca:P ratios over a range of calcium intakes will be assessed, and the response of alveolar bone contrasted with other skeletal sites.